Method for increasing the sugar content of sugar cane



United States Patent 3,482,961 METHOD FOR INCREASING THE SUGAR CONTENT OF SUGAR CANE Louis G. Nickel] and Tyrus T. Tanimoto, Honolulu,

Hawaii, assignors to Hawaiian Sugar Planters Association, Honolulu, Hawaii, an unincorporated non-profit agricultural association of Hawaii No Drawing. Filed Apr. 5, 1967, Ser. No. 628,554 Int. Cl. A01n 5/00 US. Cl. 71-121 5 Claims ABSTRACT OF THE DISCLOSURE The maturation of growing sugar cane is accelerated and the sucrose accumulation in it is increased by applying an effective amount of a N,N-di-lower alkyl-N-higher alkyl-N-Z-hydroxyethyl ammonium salt, generally as in aqueous solution, to the sugar cane several weeks before harvest.

BACKGROUND OF THE INVENTION This invention relates to a process for controlling the maturation and sucrose accumulation in growing sugar cane. It has been surprisingly and unexpectedly discovered that application to the upper portion, particularly the leaves and growing point (spindle area) of the sugar cane plant, with any of a series of N,N-di-lower alkyl-N-higher alkyl-N-2-hydroxyethyl ammonium salts several Weeks before harvest, suppresses the terminal growth of the sugar cane, thereby, in effect, inducing an early ripening of the sugar cane and thus increasing the sucrose content of the sugar cane.

It is presently believed that treatment with active compounds that induce artificial ripening of sugar cane apparently causes the conversion of various carbohydrates present in the growing sugar cane, especially reducing sugars into sucrose. Thus treatment of a sugar cane crop with these compounds leads to an increase in the yeld of sucrose when the crop is harvested and appropriately processed.

In the recent past, various compounds have been utilized to artificially ripen growing sugar cane. Invariably, these compounds have been applied to the sugar cane several weeks prior to harvesting. One series of compounds has included the halo-substituted benzoic acids, particularly 2,3,6-trichlorobenzoic acid and its salts, as shown in US. 3,245,775. Unfortunately, this latter compound is somewhat phytotoxic. A further disadvantage in its use, is the fact that it is apparently quite resistant to microbiological degradation, and consequently persists in unaltered form in the plant and in the soil for considerable periods of time, see T. W. Donaldson and C. L. Foy, Weeds, 13, 195 (1965); W. M. Phillips, Weeds, 7, 284 (1959). This undesirable property is also evidenced by the fact that when this compound is applied to wheat foliage or roots, it is found in both the seeds and straw of the plant at harvest, and when fed to rabbits and mice some of the compound is isolated from the excreta, see P. G. Balayannis, M. S. Smith and R. L. Wain, Ann. Appl. Biol., 55, 149 (1965). It is therefore probable that pharmacologically significant amounts of this compound will appear in harvested cane, and it is not inconceivable that some might appear in the final processed sugar after harvesting and processing cane to which this type of compound has been applied.

Another series of compounds which have been used in ripening sugar cane are substituted uracils and derivatives thereof, (see A. W. Evans, US. Patent 3,291,592, Dec. 13, 1966).

We have now found that the N,N-di-lower alkyl-N- "ice higher alkyl-N-2-hydroxyethyl ammonium salts are more effective in artifically ripening sugar cane than any of the compounds hithereto known and used for this purpose. In addition, these compounds have the further advantage of being biodegradable and not unduly phytotoxic.

SUMMARY OF THE INVENTION This invention comprises a method of accelerating the maturation of growing sugar cane and increasing the sucrose accumulation therein by applying thereto several weeks before harvest compounds of the general formula:

wherein R and R are lower alkyl groups containing from 1 to 4 carbon atoms; R is a higher alkyl group containing from 6 to 20 carbon atoms, and X is a nonphytotoxic anion, e.g., chloride and bromide ion.

The compounds of the present invention are applied to the tops of growing sugar cane, preferably about 2 to 10 weeks before harvesting time, by any of the usual means well-known in the art, for instance by spraying them in the form of an aqueous solution, preferably containing a surfactant in order to provide more effective Wetting of the plant.

The spraying can be accomplished either by a mechanical or hydraulic agricultural sprayer, or alternatively from an airplane, the exact mode depending upon the size of the area to be sprayed. The application of these compounds to the upper portion of the growing sugar cane plant suppresses the terminal growth thereof and artifically ripens the plant and increases its sucrose content. Thus when the sugar cane, treated as described above, is subsequently harvested and processed by methods Well-known to those skilled in the art, the yields of sugar obtained are considerably increased, as compared with those obtained from non-treated sugar cane.

DETAILED DESCRIPTION OF THE INVENTION The compounds of the present invention can be readily prepared by utilizing procedures well-known to those skilled in the art, similar to those employed in the preparation of tetralkylammonium salts, for example, see B. Tchoubar, French Patent 1,122,406, Sept. 6, 1956 and Belgian Patent 637,686, Mar. 20, 1964.

The alkyl groups of these compounds, viz., R R and R may be either branched or unbranched and the anion, X, of the relevant trialkyl hydroxyethyl ammonium salts of the present invention may be any nonphytotoxic anion such as chloride and bromide. Although we prefer to use these compounds in the form of the chlorides and bromides, the corresponding iodides, acetates, sulfates, lactates, citrates, etc., can also be employed.

These salts are readily soluble in water and may be conveniently dissolved in that medium for application to the sugar cane. The amount of compound to be applied may vary from about 2 to 10 pounds per acre. We ordinarily dissolve this amount of salt in about 6 to 15 gallons of water, the exact volume depending upon the amount of salt to be applied to the sugar cane.

It has also been found desirable to add a suitable surfactant to the aqueous salt solution in order to provide more effective wetting of the sugar cane by the applied salt solution. We prefer to use about 0.05 to 1% weight/ weight (w./w.) of surfactant to the aqueous solution. Normally we add the surfactant to the water before adding the salt, but this operation is not critical and the salt may be added first. We prefer to use non-ionic surfactants such as "Iergitol NPX (nonyl phenyl ether of polyethylene glycol), Tergitol XD (polyalkylene glycol ether), and the Carbowax polyethylene glycols, all available from Union Carbide Corp., New York, N.Y. Other suitable non-ionic surfactants which may be employed can be found in Detergents and Emulsifiers-Up-to-Date, John W. McCutcheon, Inc., Morristown, NJ. 1962. Although we prefer to apply these compounds as aqueous solutions, other suitable carriers include oils, e.g., hydrocarbons, and oil-water emulsions.

The compounds of the present invention are usually applied to the growing sugar cane about 2 to 10 weeks before harvest and preferably about 4 to 5 weeks before harvest. Aqueous solutions of these compounds may conveniently be applied to the plants either by spraying from airplanes, or by means of standard agricultural sprayers.

Although the exact biochemical processes which occur in the growing plants after contact with the salts de- The following examples are provided to more fully illustrate the present invention, but are not to be construed as limiting the scope thereof in any way.

EXAMPLE I About 4 weeks before harvesting, 38 mg. of N,N-dimethyl-N-octadecyl-N-2-hydroxyethyl ammonium chloride are dissolved in a small amount of water that contains about 0.5% (w./w.) of Tergitol NPX, and such a resultant solution is applied to the tip of each of ten 23- month old growing sugar cane stalks.

This treatment suppresses terminal growth of the sugar cane plant.

After the treated and control cane plants are harvested, the top joints of each plant are removed, combined, and analyzed, as previously described, to give the results below:

Pol

Juice percent Purity Cane Control 78. 68 9. 68 N ,N-dimethyl-N-oetadecyl-N-2'hydroxyethyl ammonium chloride 84. 72 ll. 77

1 Results of the analysis of 10 non-treated sugar cane stalks.

scribed herein is not fully understood, it appears that these compounds suppress the growth of the terminal portion of the plant, the overall effect being an artificial ripening of the sugar cane plant. It also seems that various carbohydrates in the plant are converted to sucrose. Consequently, when the treated sugar cane is harvested there is a significant increase in the total yield of sucrose from EXAMPLE II The procedure of Example I is followed with the exception that the solution of N,N-dimethyl-N-octadecyl- N-Z-hydroxyethyl ammonium chloride is applied to the plants about 5 weeks before harvesting. The results below are obtained:

Juice Percent Purity Cane ()ontrol 77. 16 9. 4G N,N-dimethyl-N-octadecyl-N-2-liydroxyethyl ammonium chloride. S4. 89 12. (it) 1 Results of the analysis of 10 non-treated sugar cane stalks.

EXAMPLE III About 8 weeks before harvesting, mg. of N,N dimethyl-N-octadecyl-N-Z-hydroxyethyl ammonium chloride are dissolved in a small amount of water containing about 0.5% (w./w.) of Tergitol NPX, and such a resultant solution is applied to the tip or spindle of each of ten 13-month old growing sugar cane stalks. After the treated and control plants are harvested, the top 15 joints of each plant are removed, combined, and analyzed as previously described, to give the results below:

Pol

Juice Percent Purity Cane Control 84. 50 11. 45 N,N-dimethyl-N-octdecyl-N-2 hydroxyethyl ammonium chloride..- 88. 05 14.40

\ Results of the analysis of 10 non-treated sugar cane stalks.

of the same age, are similarly processed to provide a control. A comparison of the values obtained for the treated cane with the control sample provides a convenient means of determining the effectiveness of these compounds as ripening agents.

The analyses are carried out by the press method of cane analyses, developed by T. Tanimoto and reported in Hawaiian Planters Record, volume 57, p. 133. The data are expressed as Juice Purity and P01 percent Cane. Pol percent Cane is a polarimeteric determination and will equal the percentage of sucrose if it is the only substance in the solution which will rotate the plane of polarized light. In any event, a determination of Pol percent Cane is considered by those skilled in the art as an effective m n of determining the sucrose content of sugar cane uice.

EXAMPLE IV EXAMPLE V Following the procedure described in Examples I to 1V, substantially the same results are obtained when N,N-dirnethyl-N-octadecyl-N-2-hydroxyethyl ammonium chloride is replaced by the compounds in the table below.

6 wherein:

R and R are alkyl groups containing from 1 to 4 carbon atoms;

R is an alkyl group containing 6 to 20 atoms; and

X is a nonphytotoxic anion.

2. The method of claim .1, wherein the active compound is selected from the group having the said formula of claim 1, wherein:

R and R are CH R is n-C H and X is a nonphytotoxic anion.

3. The method of claim 1, wherein the active compound is N,N dimethyl-N-n-octadecyl-N-Z-hydroxyethyl ammonium chloride.

4. The method of claim 1, wherein the active compound is applied as an aqueous spray, said aqueous spray being formed from an aqueous solution containing 2 to 10 pounds of active compound per 6 to 15 gallons of water.

5. The method of claim 1, wherein 2 to 10 pounds of active compound per acre of growing sugar cane are applied.

References Cited Nickell et al., Haw. Sugar Technol., 24th Annual Conference, Nov. 15 to 18, 1965 pp. 152 to I63.

JAMES O. THOMAS, JR., Primary Examiner 

